Trouble acquisition with Picoscope3404A

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haithem
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Joined: Mon May 06, 2013 4:02 pm
Location: Paris, france

Trouble acquisition with Picoscope3404A

Post by haithem »

Hi,
i'm trying to do a simple aquisition under Linux installed on a virtual machine "vmware", using the Test example "PS3000Acon.c" .but results are completly incoherent.
So i want to ask if anyone has tried to use pico with linux on a virtual machine.

Thanks for your help.

Martyn
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Location: St. Neots

Re: Trouble acquisition with Picoscope3404A

Post by Martyn »

I have used Ubuntu on Vmware with the two channel variants in the 3000 series, not the four channel.

What do you mean by
results are completly incoherent.
Martyn
Technical Support Manager

haithem
Newbie
Posts: 0
Joined: Mon May 06, 2013 4:02 pm
Location: Paris, france

Re: Trouble acquisition with Picoscope3404A

Post by haithem »

First thank you for your quick reply.
By incoherent results, i mean that i did'nt find the expected voltage.
infact:
I was trying to do aqcuisition of 13/18V DC Electrical Signals.
on windows i find correct results when using the refrence picoscope software which certifes a valid input signal and the hardware (the picoscpe itself)
After that i tried to do the same thing under Linux using the ps3000a Linux-DSK and the test example PS3000Acon.c
I excatly followed the instrutions given in the refrence linux software. i compile it ,as required and start doing some tests as follow:

input signal : 13V DC (connected on input A) and 18V
input B , C, D not connected.
set voltage range "V" to 20V on the 4 inputs (A,B,C,D)
perform a capture of block using block Mode capture: "B"/streaming Mode: "S"

Results:
--with Block Mode "B": the results are far from 13V/18V, the maxVoltage are negatif and the minV are positif
---But when i use the Streaming Mode "S": i note a factor of 2( for 13V , i have ~6500 mV and for 18V i have ~9000mV)

I tried to push further and investigate this use case(streaming Mode) and found that the results of the input A changes if i desactivate the non used input B,C,D i.e: i have different results on input A when i desactivate "B" set voltage to 99", or/and "C" or/and "D"

Hence even the "2" factor i noted on the streaming mode becames obsolete.

Finally i want to ask you if it is possible to give us an image of the Linux virtual Machine that you used for the test and i will be so grateful because it's a emergency for me.?


Thank you
Best regards
Haithem

Martyn
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Re: Trouble acquisition with Picoscope3404A

Post by Martyn »

Sorry can't give you a copy of the virtual machine, it contains information I am not allowed to release.

What adc count values are being returned by the driver before you convert them to mV ?
Martyn
Technical Support Manager

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